Basophil Activation Test with Indomethacin to Assess Hypersensitivity to Non-Steroidal Anti-Inflammatory Drugs: A Preliminary Study

Background: The basophil activation test has been investigated for diagnosing hypersensitivity to non-steroidal anti-inflammatory drugs (NSAIDs). This has not yet been done in relation to indomethacin. Objective: First seek to establish the viable concentrations of indomethacin and the diluent propylene glycol (PPG) in relation to basophils then test this in patients with hypersensitivity to NSAIDs. Materials & Methods: The ideal concentrations of PPG and indomethacin were assessed by incubating them with basophils from an atopic donor and evaluating the intensity of expression of CD63 molecules by means of flow cytometry. We also evaluated the cell viability directly using the trypan blue in seven controls. Then indomethacin was tested in ten patients with hypersensitivity to NSAIDs compared with eight persons in control group. Results: In relation to the toxicity of propylene glycol, concentrations less than or equal to 0.5% are safe. There was no cytotoxicity or nonspecific stimulation from using indomethacin at concentrations of 10 mcg/mL, 1 mcg/mL and 0.1 mcg/mL. Then indomethacin was tested at concentration of 10 mcg/mL diluted in 0.5% propylene glycol in both groups. There was no statistical difference in the intensity of activation of basophils comparing the group of patients with hypersensitivity to NSAIDs and the control group. Conclusions: As a diluent for indomethacin, PPG should be used at concentrations less than or equal to 0.5%. The indomethacin at concentration of 10 mcg/mL was not able to differentiate patients with and without hypersensitivity to NSAIDs.